Class 8 Science - Chapter Sound NCERT Solutions | In the following statements, tick T agai
In the following statements, tick T against those which are true, and F against those which are false:
(a) Sound cannot travel in vacuum. (T/F)
(b) The number of oscillations per second of a vibrating object is called its time period. (T/F)
(c) If the amplitude of vibration is large, sound is feeble. (T/F)
(d) For human ears, the audible range is 20 Hz to 20,000 Hz. (T/F)
(e) The lower the frequency of vibration, the higher is the pitch. (T/F)
(f) Unwanted or unpleasant sound is termed as music. (T/F)
(g) Noise pollution may cause partial hearing impairment. (T/F)
(a) True
This statement is true because sound cannot travel in vacuum. Sound is produced by vibrations. If there, air is not present then sound cannot be produced.
(b) False
This statement is false because the number of oscillations per second of a vibrating object is called its frequency.
(c) False
This statement is false if the amplitude of vibration is large, then the sound will be sharp and having a high pitch.
(d) True
This statement is true because the range of hearing a sound is 20 Hz to 20000 Hz. Above 20,000 Hz the sound is not audible and harmful for ears.
(e) False
This statement is false because as higher is the frequency, the pitch of the sound is high.
(f) False
This statement is false because the unwanted and unpleasant sound is termed as noise pollution whereas the pleasant sound is known as music.
(g) True
This statement is true because noise pollution is harmful to the ears and it may cause partial hearing impairment. The unwanted and unpleasant sound is known as noise pollution.
More Questions From Class 8 Science - Chapter Sound
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Explain in what way noise pollution is harmful to humans.
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List sources of noise pollution in your surroundings.
- Q:-
Fill in the blanks with suitable words.
(a) Time taken by an object to complete one oscillation is called ................... .
(b) Loudness is determined by the .........................of vibration.
(c) The unit of frequency is..........................
(d) Unwanted sound is called ......................... .
(e) Shrillness of a sound is determined by the ................. of vibration. - Q:-
Lightning and thunder take place in the sky at the same time and at the same distance from us. Lightning is seen earlier and thunder is heard later. Can you explain?
- Q:-
Which of the following voices is likely to have minimum frequency?
(a) Baby girl (b) Baby boy
(c) A man (d) A woman - Q:-
Identify the part which vibrates to produce sound in the following instruments:
(a) Dholak (b) Sitar (c) Flute - Q:-
A pendulum oscillates 40 times in 4 seconds. Find its time period and frequency.
- Q:-
What is the difference between noise and music? Can music become noise sometimes?
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Fill in the blanks
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(b) A copper rod
(c) An inflated balloon
(d) A woollen cloth. - Q:-
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(b) Species found only in a particular area is known as .
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Suppose you are in a dark room. Can you see objects in the room? Can you see objects outside the room. Explain.
- Q:-
What are the different ways in which water gets contaminated ?
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